Figure 7-63.Guided-bend test specimens.test piece by using a hydraulic press or similar machine.When the proper precautions are taken, a blacksmithsforging press or hammer can be used to complete thebending operation. If a crack more than 1/16 inch devel-ops during the test, stop the bending because the weldhas failed; otherwise, bend the specimen flat. Aftercompleting the test, measure the distance between thescribed lines and call that measurement (y). The percent-age of elongation is then determined by the formula:Requirements for a satisfactory test area minimumelongation of 15 percent and no cracks greater than 1/16inch on the face of the weld.Guided-Bend TestYou use the GUIDED-BEND TEST to determinethe quality of weld metal at the face and root of a weldedjoint. This test is made in a specially designed jig. Anexample of one type of jig is shown in figure 7-62.The test specimen is placed across the supports ofthe die. A plunger, operated from above by hydraulicpressure, forces the specimen into the die. To fulfill therequirements of this test, you must bend the specimen180 degreesthe capacity of the jig. No cracks shouldappear on the surface greater than 1/8 inch. The face-bend tests are made in this jig with the face of the weldin tension (outside), as shown in figure 7-63. The root-bend tests are made with the root of the weld in tension(outside), as shown in figure 7-63.Figure 7-64 shows a machine used for making theguided-bend test. It is used in many welding schools andFigure 7-64.Testing machine for making guided-bend tests.7-39